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Built for Moisture: How Warmset Exceeds the Standard in Safety

Written by

Warmset Australia

24 November 2025

 • 

3 min read

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We recently received an enquiry asking if sealing the slab was required when using Warmset. This prompted us to write an article about this important distinction between Warmset and other electric heating mats.

Understanding Moisture Risks in Electric Underfloor Heating

Underfloor heating systems live beneath your floors, so it’s important they are built to withstand moisture from the environment. Moisture can come from two main sources:

  1. Rising Damp: Moisture that seeps up from the ground or the concrete slab.
  2. Ambient Humidity: Moisture from inside the room, especially in bathrooms, kitchens, saunas, or pool areas.

How Warmset Is Built Differently

Our globally patented heating ribbon is made of multiple layers of insulation (11 layers in total, including the heating core in the middle). This multi-layer structure does two important things:

  • It protects the internal conductor (the part that heats up).
  • It allows the outer protective layer to be connected to your home’s electrical earthing system.

Why is this so important? Because grounding (earthing) protects you in case of any damage to the electric heating mat, and it helps your safety switches (like the RCD or “safety switch”) detect faults instantly and shut off power.

What is Step Voltage and Why Does It Matter?

Step voltage is the difference in electrical potential between two points on the ground—like the difference between your two feet. If a fault occurs and there’s no grounding, you could be at risk of electric shock even without touching anything.

Warmset helps prevent this because its outer insulation layer can be grounded. This reduces step voltage to near zero and activates safety devices quickly in the event of a fault.

Moisture Protection Best Practices

Even with Warmset’s superior build, in moisture-prone areas, such as bathrooms or wellness centres, we recommend following these additional steps:

  • For Rising Damp: Before installing the heating mat, apply a polyethylene film or a waterproof flexible membrane (such as Mapei Mapelastic) directly over the slab.
  • For Ambient Humidity: After installing the electric underfloor heating system, you can either:
    • Place a polyethylene film over the heating ribbon before tiling, or
    • Apply a waterproofing layer on top of the screed once the mat is embedded (which is already standard practice).

What About Other Brands?

Many cheaper or mass-produced electric cable heating mats only have one or two layers of insulation and can’t be connected to the earthing system. This means they lack the safety and durability features that Warmset offers as standard.

Check out our dedicated article about this specific topic, comparing in more details Warmset with electric cable heating mats.

In Summary

  • Warmset’s unique design offers better moisture resistance and electrical safety.
  • Grounding capability adds another layer of protection.
  • Even so, in wet areas, always apply an extra moisture barrier for peace of mind.
  • Compared to many competitors, Warmset gives you higher confidence, better construction, and long-term performance.

Stay safe, warm, and worry-free—with Warmset under your feet.